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Need help creating a modified version of the NOR block

Posted 5 years ago
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Hi! I need help regarding modifying the NOR block.

I have been trying to achieve a NOR block such that when I input all 0's in it, it gives me a 1 for 5 seconds, and then reverts back to 0.

Here's how I have modified the NOR block so far:

block ModifiedNOR
parameter Modelica.SIunits.Time startTime = time;
extends Blocks.Interfaces.partialBooleanSI2SO;
when (u1=u2)
equation
y = if startTime+5>time true else false;
end ModifiedNOR;

I would appreciate if someone shows me where am I mistaken. Thanks.

Hi Safi Ahmed!

You need to have an event that changes a time variable that keeps track of when the values of u1 and u2 last where 0 at the same time, and then check if it has been within 5 seconds since last this occurred. Does the following code work as you intended your NOR block? Once you input two 0:s, it will give a 1 for 5 seconds (even if one of the inputs changes during that time).

model ModifiedNOR
extends Modelica.Blocks.Interfaces.partialBooleanSI2SO;
protected
  discrete Modelica.SIunits.Time entryTime "Time instant when NOR became true";
initial equation
  pre(entryTime) = 0;
equation
  when not (u1 or u2) then
    entryTime = time;
  end when;
  y = if time - entryTime < 5 then true else false;
  annotation(Diagram(coordinateSystem(extent = {{-148.5, -105}, {148.5, 105}}, preserveAspectRatio = true, initialScale = 0.1, grid = {5, 5})));
end ModifiedNOR;

Here are some resources if you want to learn more about events and when-statements.

Hope that helps!

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